Acute Liver Transplant Rejection Research Articles

Pharmacokinetics of free mycophenolic acid and limited sampling strategy for the estimation of area under the curve in liver transplant patients

Mycophenolate Mofetil (MMF) is widely used in preventing acute rejection in liver transplantation. Only free MPA (fMPA) can exert the pharmacological effect. In this study, we aimed to develop the new model which could be best fit to predict the fMPA area under the plasma concentration–time curve (AUC) by limited sampling strategy (LSS) in Chinese liver transplant patients. Fifty patients received MMF with the combination of tacrolimus. Free MPA concentrations were determined around day 7. Optimal subset regression analysis was used to establish the models for estimated fMPA AUC0–12h. Three excellent better models were validated by Bootstrap analysis. Twenty-four models including four blood time point samplings were established. For the selected four models, 100% were successful and were not significantly different from the original dataset by Bootstrap analysis. The best model for prediction of fMPA AUC0–12h was by using C1h, C2h, C4h and C6h. This model showed the minimal mean prediction error and the minimal mean absolute prediction error. In conclusion, the models for estimation of the fMPA AUC0–12h were established in liver transplant recipients and the best model for prediction of fMPA AUC was: estimated fMPA AUC=34.2+1.12C1h+1.29C2h+2.28C4h+3.95C6h.

Serum Levels of Interleukin-9 During Acute Rejection in Liver Transplantation

IntroductionInterleukin-9 (IL-9) has been cast as a player in autoimmunity, but its role in liver transplantation remains to be clarified. The aim of our study was to investigate the time course of IL-9 serum levels during hepatic allograft rejection. MethodsIL-9 serum levels were determined in 34 healthy subjects and 50 hepatic transplant recipients. The patients were divided into two groups: group I was composed of 15 patients with acute rejection episodes, and group II, 35 patients free of this problem. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy. ResultsThe concentrations of IL-9 were similar in the rejection and nonrejection groups over the entire postoperative period. The whole transplant group, including those with stable graft function, showed higher IL-9 serum levels than the controls at all times after liver transplantation. ConclusionsThese preliminary results suggest a lack of participation of IL-9 in human liver allograft rejection.

IDO-Competent-DCs Induced by IFN-γ Attenuate Acute Rejection in rat Liver Transplantation

We established a stable rat model of liver transplantation using Sprague-Dawley rats and Wistar rats in order to investigate the role of the IDO gene in acute rejection after rat liver transplantation. IDO gene expression and IDO enzyme activity were quantified in liver syngeneic grafts and allografts using microdialysis-HPLC. Liver allografts were evaluated for IDO expression by histopathology. We measured liver function-related biomarkers in liver allografts which were re-infused with untreated or IFN-γ-treated dendritic cells (DCs). We found a significant increase in IDO gene expression and IDO enzyme activity in liver allografts compared the sham and syngeneic graft groups. There was a significant correlation between the number of IDO-positive cells and severity of acute rejection. IDO gene expression and enzyme activity was upregulated in the IFN-γ-treated DC group within 7days after transplantation compared to the untreated DC group and survival rates were significantly improved. Our results suggested that IDO gene expression correlates with the severity of acute rejection and that IFN-γ-induced IDO-positive DCs may attenuate acute rejection and catalyze local tryptophan metabolism via IDO enzyme expression, leading to immune tolerance after liver transplantation.

The Risk Factors to Predict Acute Rejection in Liver Transplantation

PurposeThe aim of this study was to evaluate risk factors for an acute cellular rejection episode (ARE) among adult liver transplant (OLT) patients. Materials and methodsWe retrospectively reviewed 110 consecutive patients who underwent OLT between May 2007 and December 2010. The diagnosis of ARE was based upon clinical and biochemical data; liver biopsy was only performed when clinical presentation was equivocal. We recorded donor and recipient characteristics, perioperative immune status, and postoperative laboratory data. Forty patients (36.4%) who suffered a clinical rejection episode and received pulsed or recycled steroid therapy (R group), were compared with 70 (63.6%) free of rejection (N group). ResultsThe mean age of R recipients was 46.61 ± 9.97 years, which was younger than the N group (51.86 ± 8.37, P = .005). R group patients displayed a lower pre-OLT creatinine (P = .016) and higher alanine aminotransferase (P = .048). Cox regression model showed recipient age to be the only significant factor to predict ARE (odds ratio = 1.071, P = .003). The cutpoint of age was 46 years by receiver operating characteristic analysis. Patients younger than 46 years showed higher initial CD8+ T-cell counts (P = .038). ConclusionRecipient age was significantly associated with ARE; younger patients showed higher CD8+ lymphocyte counts than older patients. More aggressive immunosuppression should be considered for younger recipients to prevent ARE.

Does Lymphocyte Cross-Matching Predict Acute Rejection and Graft Survival in Liver Transplantation?

IntroductionThe role of lymphocyte cross-matches (LCM) remains controversial in the liver transplant field. The aim of this study was to correlate the risk for acute rejection episodes and graft survival in liver transplantation with pretransplant LCM results. Patients and MethodsWe enrolled 184 adult liver transplantation patients, excluding pediatric and second grafts. The 129 living donor and 55 deceased donor liver transplantations were divided into 2 groups: LCM (+); (n = 20) and LCM (−); (n = 164). ResultsThere were no differences in the demographic features, such as gender and recipient age, original disease, Model for End-Stage Liver Disease score, donor type, number of human leukocyte antigen mismatches, and cold ischemia times. There were no hyperacute rejection episodes in the LCM (+) group. Also, posttransplant complications such as acute rejection episode, biliary complication, or hepatic artery thrombosis were not different. Acute rejection episodes occurred in 5.0% of the LCM (+) group and 15.2% of the LCM (−) group (P = .317). Bile duct complications after transplantation arose in 20.0% of the LCM (+) group and in 32.9% of the LCM (−) group (P = .312). The 2 groups showed no difference in graft survival rate analyzed by the Kaplan–Meier method according to LCM results. ConclusionPretransplant LCM results were not associated with overall graft survival or acute rejection episodes in this study.

Effect of early EBV and/or CMV viremia on graft function and acute cellular rejection in pediatric liver transplantation

The clinical impact of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections in the early post-transplantation period are poorly documented. We investigated the prevalence and timing of EBV and CMV infections during the first 21 d post-transplantation in relation to graft function and acute cellular rejection in a large cohort of pediatric liver transplantation recipients. Clinical, biochemical, virological, and histopathological data of 62 consecutive children who received a liver transplant were reviewed retrospectively. Seventeen patients (27%) developed EBV and 11 (18%) CMV viremia (mean interval from surgery: 7.6 d, SD 3.6 and 8.7 d, SD 6.4, respectively). EBV and CMV viremia were more common as a consequence of reactivation than of primary infection. EBV viremic recipients had more often abnormal bilirubin levels [p = 0.01; OR 5.8: 95% CI 1.3-25.5]. Acute rejection was diagnosed in 20 recipients (32.3%). No correlation was found between rejection and EBV and CMV serology before transplantation and viremia after transplantation (mean interval between the diagnosis of rejection and the detection of EBV DNA and CMV DNA: one d, SD 4.4 and five d, SD 9.2, respectively). EBV and CMV viremia occur at a very early-stage post-transplantation and do not appear to affect the short-term outcome of the transplant.

Expression of glucocorticoid induced tumor necrosis factor receptor ligand during acute rejection after rat liver transplantation

Objective To investigate te changes of glucocorticoid induced tumor necrosis factor receptor ligand (GITRL) in hepatic allograft rejection. Methods Liver transplantation from Lewis rats (n = 5 ) to Brown Norway (BN) rats was performed by Kamada' s two-cuff technique as acute rejection group. Liver transplantation from BN to BN rats ( n = 5 ) was performed as tolerance group. Recipients were sacrificed at 24th h postoperation. Blood samples were collected and grafts were harvested, then Kupffer cells were isolated. GITRL and tumor necrosis factor (TNF)-α protein expression in the hver was tested by immunohistochemistry, and the GITRL expression in Kupffer cells by immunocytochemistry. Enzyme linked immunosorbent assay (ELISA) was employed to detect the changes of TNF-α protein in the serum and supernatant. The staining intensity was analyzed by Image-Pro Plus 6. 0 image analysis software. Results At 24th h postoperation, the liver GITRL expression levels in tolerance and rejection groups were 0. 113 ± 0. 007 and 0. 270 ±0. 018, respectively (P ＜0. 05). The TNF-α expression levels in the liver in tolerance and rejection groups were 0. 114 ± 0. 004 and 0. 141 ± 0. 005 respectively ( P ＜ 0.05 ). The GITRL expression levels in Kupffer cells in tolerance and rejection groups were 0. 206 ±0. 017 and 0. 337 ±0. 018 respectively (P ＜0. 05 ). As compared with tolerance group (68. 66 ±21.12) ng/L, TNF-α protein expression levels were up-regulated in the supernatant of rejection group ( 178.33 ± 29. 39 ) ng/L ( P ＜ 0. 05 ).Conclusion The expression of GITRL in the liver and Kupffer cells was increased in the early stage of rejection, and monitoring and interfering GITRL may be useful for the early diagnosis and management of an acute rejection in liver transplantation. Key words: GITRL; Liver transplantation; Acute rejection; Kupffer cells

Expression of Glucocorticoid-Induced Tumor Necrosis Factor Receptor Ligand in Rat Graft after Liver Transplantation

Background Costimulation between the glucocorticoid-induced tumor necrosis factor receptor and its ligand (GITRL) breaks immunologic tolerance induced by regulatory T cells. The purpose of this research was to examine the involvement of GITRL during rat liver transplantation, the survival of which depends on interactions between regulatory T cells and Kupffer cells (KCs). Methods Recipients were divided into 2 groups: The allograft group underwent orthotopic liver transplantation from male Lewis to Brown Norway (BN) rats and the isograft group, BN-to-BN liver transplantation. We evaluated 2-week survival rates, histologic changes, as well as serum and supernatant levels of tumor necrosis factor-α (TNF-α); GITRL, and TNF-α expressions in the graft, and GITRL expression by graft-derived KCs. Results TNF-α levels were increased in plasma and in the supernates of KCs during allograft transplantation compared with isograft liver transplantation ( P <.05). The expressions of TNF-α and GITRL in liver grafts were increased during acute rejection. Furthermore, the expression of GITRL on KCs derived from allografts was increased compared with isografts ( P < .05). Conclusion GITRL expression on KCs may mediate acute rejection in liver transplantation.

Perfusion Fluid Contamination in Relation to Recipient Survival and Acute Cellular Rejection in Orthotopic Liver Transplantation: Retrospective Analysis

Introduction A perfusion fluid used in the preservation of a grafted liver represents a medium suitable for microorganism growth. This study investigated the prevalence of perfusion fluid contamination, acute cellular rejection (ACR) episodes, and patient survival rate. Method This is a retrospective study, based on an electronic database allocating cases of orthotopic liver transplantation. The exclusion criteria were as follows: having been submitted to multiple organ transplantation, liver retransplantation only, and those whose samples had not been collected or sent on the back table procedure or were unobtainable (usually the samples were sent when there was donor infection suspicion/positivity). Our posttransplantation infection prophylactic protocol consisted of ampicillin/sulbactam for 72 hours. The variables in the study were as follows: fluid contamination, presence of acute cellular rejection (ACR, Banff classification), and recipient survival at the first year. Statistical analysis was performed using descriptive statistics and chi-square with Fisher exact test considering significant P < .05. Results We observed perfusion fluid contamination in 15/121 (12.39%). The agents were as follows: Klebsiella pneumoniae in 6 (4.96%), Staphylococcus epidermidis in 5 (4.13%), and Acinetobacter baumanii in 3 (2.48%) and negative cultures in 106 (87.60%). Only 1 patient had matching for donor infection and positivity hemoculture after the transplantation ( K pneumoniae) and he was the only patient associated with fluid infection and death. The recipients who had their fluid preservation with positive cultures had more ACR and the survival rate was similar among those with or without infection. Conclusion Optimization of microbiological procedures can be performed including fungal and bacterial cultures.

Basiliximab as therapy for acute rejection after liver transplantation for hepatitis C virus cirrhosis

Steroid bolus therapy for acute rejection after liver transplantation for hepatitis C virus (HCV) cirrhosis often results in graft loss due to adverse effects. The efficacy and safety of basiliximab for the treatment of acute cellular rejection (ACR) in adult liver transplantation has not been adequately evaluated. Three patients received basiliximab as rescue therapy for acute rejection. The outcome and biochemical parameters were recorded before and after treatment with basiliximab. These results were compared to 11 patients who received steroid therapy for ACR. The median time from transplantation to the development of ACR was 19 days (range, 9-49 days). The degree of ACR was mild or moderate. Resolution of rejection was obtained in all patients and the median time from the onset to resolution of ACR was 16 days (range, 6-41 days). A steroid resistant reaction occurred in 2 of 11 patients and OKT3 was used, and the rejection eventually resolved in all patients. Five patients died within 2 to 22 months after transplantation and four of them died from graft failure. In the basiliximab group, there were no significant immediate adverse effects. One patient died from pneumonia 8 months after transplantation. Basiliximab can be safely used as rescue therapy for ACR without significant adverse effects in patients who underwent liver transplantation for HCV cirrhosis.

Association of IL-6 promoter and IFN-γ gene polymorphisms with acute rejection of liver transplantation

Liver transplantation is one of the most important therapies for end-stage liver diseases and is associated with major problems including infections and acute rejection. The outcome of transplantation can be determined by immune responses as a key role in response to the graft. Inflammatory and anti-inflammatory mediators especially cytokines influence the graft microenvironment. Th1 and Th2 immune responses in contrast to regulatory responses cause acute rejection or help graft survival. In this study, we evaluated the gene polymorphisms of IL-6 G-174C, TGF-β T + 869C, IL-4 C-590T, and IFN-γ T + 874A cytokines in liver transplant patients. ARMS-PCR method was used to characterize IL-6 G-174C, TGF-β T + 869C and IFN-γ T + 874A polymorphisms and PCR-RFLP using AvaII restriction enzyme was done for IL-4 C-590T characterization in 70 liver transplant patients. Acute rejection episodes were diagnosed according to standard criteria. The analysis of the results showed that IL-6-174 GG genotype ( P = 0.009, OR = 4.333, 95% CI = 1.043-18.000), IL-6-174G allele (P = 0.011, OR = 5.273, 95% CI = 1.454-19.127) was more frequent and IFN-γ +874 TT genotype was less frequent (P = 0.043, OR = 0.143, 95% CI = 0.0118-1.190) in acute rejection than in non-rejection patients. TGF-β T + 869C and IL-4 C-590T frequencies were not significantly different (P > 0.05). According to the results, it can be conclude that IL-6 G-174C and IFN-γ T + 874A gene polymorphisms have predictive values for acute rejection after liver transplantation. High producer genotype of IL-6 is a genetic risk factor and IFN-γ is a protective factor for acute rejection development.

Hepatofugal portal flow associated with acute rejection in living-donor auxiliary partial orthotopic liver transplantation: A report of one case and literature review

We report a case of reversible hepatofugal portal flow after auxiliary partial orthotopic liver transplantation (APOLT) from a living donor in this study. On postoperative day 6, continuous hepatofugal portal flow was observed in the grafted liver without portal thrombosis and obstruction of the hepatic vein. Based on histological findings, acute rejection was the suspected cause. The normal portal venous flow was restored after steroid pulse and antithymocyte globulin (ATG) therapies. The patient was discharged on the 30th postoperative day. It was concluded that hepatofugal flow after liver transplantation is a sign of serious acute rejection, and can be successfully treated by anti-rejection therapy.

Lymphangiogenesis Associated With Acute Cellular Rejection in Rat Liver Transplantation

Lymphangiogenesis may be important for the cellular immune response in liver transplantation. In the present study, we examined lymphangiogenesis in liver allografts displaying acute cellular rejection (ACR), or long-term acceptance, or severe ACR plus antibody-mediated rejection (AMR). ACR and subsequent long-term graft acceptance developed in liver transplantations from DA to PVG rats without immunosuppression (mean survival time more than 90 days). Severe ACR and AMR developed in liver transplantations from DA to Lewis rats without immunosuppression (mean survival = 11 days). Normal DA donor livers before transplantation showed a small number of lymphatic vessels around portal veins. DA liver grafts in PVG showed ACR with lymphangiogenesis in portal areas and portal-portal bridging areas with cellular infiltration. Newly formed lymphatic vessels in ACR were characterized by proliferating endothelial cells with expression of the homeobox transcription factor PROX-1 and surrounded by discontinuous basement membranes. Thereafter, the infiltrates spontaneously disappeared, and the grafts survived more than 90 days. During the resolution of the cellular infiltration, expanded lymphatic vessels were packed with many lymphocytes. Thereafter, the number of lymphatic vessels decreased. In contrast, severe ACR and AMR in DA-to-Lewis transplantations showed lymphatic vessels disappeared with edema in the portal areas at day 11. In conclusion, lymphangiogenesis occurred during ACR. It may be involved in the resolution of ACR and reduction of inflammation. In severe ACR and AMR, lymphatic vessels were destroyed, which may be involved in persistent severe inflammation.

Positive Lymphocytotoxic Crossmatch Does Not Adversely Affect Survival in Living Donor Liver Transplantation

Background/Aims: The influence of lymphocytotoxic crossmatch on survival or acute rejection in liver transplantation remains controversial. Data regarding graft survival and acute rejection of living donor liver transplantation (LDLT) are limited. Methods: We retrospectively examined the influence of a positive T or B lymphocytotoxic crossmatch on survival and acute rejection in patients using a database of 414 consecutive LDLT cases. Results: The rejection-free rate at 90 days after LDLT was lower in patients that were T crossmatch-positive compared to patients that were both T and B crossmatch-negative (52 vs. 74%, p = 0.03). No patients with a positive lymphocytotoxic crossmatch died due to immunologic causes. The crossmatch results had no effect on graft survival. Conclusion: In the positive crossmatch groups, there was no acute rejection that was untreatable or that caused graft loss. These findings indicate that a positive crossmatch graft should not be considered a contraindication for LDLT.

Acute measles infection triggering an episode of liver transplant rejection

We report the case of a 31-year-old immunosuppressed, liver transplanted man, with acute measles infection. The vaccinated patient had been exposed to measles during a known measles epidemic in public schools in Austria between January and April 2008. Measles infection triggered an episode of acute liver transplant rejection. The diagnosis of measles infection was made clinically and by serologic tests. Transplant rejection was diagnosed by liver biopsy. The transplant rejection was treated successfully. Liver transplant patients are at an increased risk for infection during epidemic outbreaks, even after pre-transplant vaccination, as immunity may wane over time.

Blockade of inducible costimulator pathway to prevent acute rejection in rat liver transplantation

Background The role of inducible costimulator (ICOS) in transplantation immunity remains unclear. Methods A Lewis-to-Brown–Norway (BN) rat liver transplant model was used to explore the effect of ICOS blockade by small interference RNA. Recipient survival rate, number of CD25/ICOS–positive cells, ICOS mRNA and protein levels, and interferon-γ and tumor-necrosis factor-α levels were determined. Results Recipient survival was significantly prolonged in rats treated with RNA interference. On day 7 after transplantation, there was a diminished frequency of CD25/ICOS–positive cells and an increased frequency of apoptotic T cells. Furthermore, we found that ICOS blockade could inhibit mRNA and protein expression of ICOS, decrease plasma levels of interferon-γ and tumor-necrosis factor-α, suppress cell infiltration into grafts, and promote tolerance in the interference group. Conclusions Our data demonstrate that RNA interference is a potent tool to down-modulate ICOS expression and protect allografts from acute rejection.

Changes in the serum levels of interleukin-17/interleukin-23 during acute rejection in liver transplantation

Interleukin-23 (IL-23) and T helper 17 (Th17) cells have been cast as major players in autoimmunity, but their role in transplantation immunity remains to be specified. The aim of our study was to investigate the time course of serum levels of IL-23 and IL-17 during hepatic allograft rejection. Serum levels of IL-23 and IL-17 were determined in 20 healthy subjects and 50 hepatic transplant recipients. These patients were divided into 2 groups: group I was composed of 15 patients with acute rejection, and group II was composed of 35 patients without acute rejection. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy. The concentrations of IL-23 were similar for the rejection group and nonrejection group at early postoperative times. We observed a significant increase in serum IL-23 levels in the rejection group when a diagnosis of acute rejection had been established. Similarly to IL-23, at the diagnosis of acute rejection, the concentration of IL-17 was significantly higher in the rejection group versus the nonrejection group. The whole transplant group, including those with stable graft function, had higher serum levels of IL-23 and IL-17 than the controls during the entire postoperative period. In conclusion, IL-23 and IL-17 are up-regulated during acute hepatic rejection. These findings suggest a role for Th17 cells in human liver allograft rejection.

Acute Liver Transplant Rejection Upon Immunosuppression Withdrawal in a Tolerance Induction Trial: Potential Role of IFN-γ-secreting CD8+ T Cells

We designed a pilot trial in cadaveric liver transplantation to determine whether induction with antithymocyte globulins (ATG) and sirolimus would allow immunosuppression withdrawal. Patients received ATG 3.75 mg/kg per day from day 1 to 5 after transplantation followed by sirolimus for 4 to 6 months. We monitored interleukin (IL)-7 serum levels, interferon (IFN)-gamma, and IL-2 mRNA accumulation in mixed leukocyte reaction and intragraft IFN-gamma mRNA expression. In the first three patients, immunosuppression discontinuation was followed by reversible acute rejection occurring on days 280, 246, and 163 posttransplantation, corresponding to days 140, 40, and 39 after drug withdrawal, respectively. At the time of rejection, blood CD8+ T-cells counts had returned to or above pretransplant levels in two of three patients, whereas CD4+ T-cell count remained low. IL-7 serum levels rose in all three patients in the first months after transplantation and IFN-gamma mRNA accumulated in mixed leukocyte reaction between recipient T cells and donor spleen cells at the time of rejection. High levels of IFN-gamma mRNA were consistently detected in liver biopsy performed at the time of rejection. In conclusion, lymphopenia-induced IL-7 production after induction with ATG and sirolimus might lead to emergence of IFN-gamma-secreting CD8+ T-cells responsible for acute rejection after immunosuppression withdrawal.

Graft fibrosis in stable pediatric liver transplant recipients: What does it mean?

Graft fibrosis in stable pediatric liver transplant recipients: What does it mean?

Acute rejection of liver transplantation: A case report.

Acute rejection of liver transplantation: A case report.